Re: [PATCH v2 2/2] drm/i915/gvt: export mdev device version to sysfs for Intel vGPU

Yan Zhao
2019-05-08T12:26:39Z

On Wed, May 08, 2019 at 06:50:33PM +0800, Dr. David Alan Gilbert wrote:
> * Yan Zhao (yan.y.zhao@intel.com) wrote:
> > This feature implements the version attribute for Intel's vGPU mdev
> > devices.
> >
> > version attribute is rw.
> > It's used to check device compatibility for two mdev devices.
> > version string format and length are private for vendor driver. vendor
> > driver is able to define them freely.
> >
> > For Intel vGPU of gen8 and gen9, the mdev device version
> > consists of 3 fields: "vendor id" + "device id" + "mdev type".
> >
> > Reading from a vGPU's version attribute, a string is returned in below
> > format: <vendor id>-<device id>-<mdev type>. e.g.
> > 8086-193b-i915-GVTg_V5_2.
> >
> > Writing a string to a vGPU's version attribute will trigger GVT to check
> > whether a vGPU identified by the written string is compatible with
> > current vGPU owning this version attribute. errno is returned if the two
> > vGPUs are incompatible. The length of written string is returned in
> > compatible case.
> >
> > For other platforms, and for GVT not supporting vGPU live migration
> > feature, errnos are returned when read/write of mdev devices' version
> > attributes.
> >
> > For old GVT versions where no version attributes exposed in sysfs, it is
> > regarded as not supporting vGPU live migration.
> >
> > For future platforms, besides the current 2 fields in vendor proprietary
> > part, more fields may be added to identify Intel vGPU well for live
> > migration purpose.
> >
> > v2:
> > 1. removed 32 common part of version string
> > (Alex Williamson)
> > 2. do not register version attribute for GVT not supporting live
> > migration.(Cornelia Huck)
> > 3. for platforms out of gen8, gen9, return -EINVAL --> -ENODEV for
> > incompatible. (Cornelia Huck)
> >
> > Cc: Alex Williamson <alex.williamson@redhat.com>
> > Cc: Erik Skultety <eskultet@redhat.com>
> > Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> > Cc: Cornelia Huck <cohuck@redhat.com>
> > Cc: "Tian, Kevin" <kevin.tian@intel.com>
> > Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
> > Cc: "Wang, Zhi A" <zhi.a.wang@intel.com>
> > c: Neo Jia <cjia@nvidia.com>
> > Cc: Kirti Wankhede <kwankhede@nvidia.com>
> >
> > Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> > ---
> > drivers/gpu/drm/i915/gvt/Makefile | 2 +-
> > drivers/gpu/drm/i915/gvt/device_version.c | 87 +++++++++++++++++++++++
> > drivers/gpu/drm/i915/gvt/gvt.c | 51 +++++++++++++
> > drivers/gpu/drm/i915/gvt/gvt.h | 6 ++
> > 4 files changed, 145 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/gpu/drm/i915/gvt/device_version.c
> >
> > diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
> > index 271fb46d4dd0..54e209a23899 100644
> > --- a/drivers/gpu/drm/i915/gvt/Makefile
> > +++ b/drivers/gpu/drm/i915/gvt/Makefile
> > @@ -3,7 +3,7 @@ GVT_DIR := gvt
> > GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
> > interrupt.o gtt.o cfg_space.o opregion.o mmio.o display.o edid.o \
> > execlist.o scheduler.o sched_policy.o mmio_context.o cmd_parser.o debugfs.o \
> > - fb_decoder.o dmabuf.o page_track.o
> > + fb_decoder.o dmabuf.o page_track.o device_version.o
> >
> > ccflags-y += -I$(src) -I$(src)/$(GVT_DIR)
> > i915-y += $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
> > diff --git a/drivers/gpu/drm/i915/gvt/device_version.c b/drivers/gpu/drm/i915/gvt/device_version.c
> > new file mode 100644
> > index 000000000000..bd4cdcbdba95
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/gvt/device_version.c
> > @@ -0,0 +1,87 @@
> > +/*
> > + * Copyright(c) 2011-2017 Intel Corporation. All rights reserved.
> > + *
> > + * Permission is hereby granted, free of charge, to any person obtaining a
> > + * copy of this software and associated documentation files (the "Software"),
> > + * to deal in the Software without restriction, including without limitation
> > + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> > + * and/or sell copies of the Software, and to permit persons to whom the
> > + * Software is furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice (including the next
> > + * paragraph) shall be included in all copies or substantial portions of the
> > + * Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> > + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
> > + * SOFTWARE.
> > + *
> > + * Authors:
> > + * Yan Zhao <yan.y.zhao@intel.com>
> > + */
> > +#include <linux/vfio.h>
> > +#include "i915_drv.h"
> > +
> > +static bool is_compatible(const char *self, const char *remote)
> > +{
> > + if (strlen(remote) != strlen(self))
> > + return false;
> > +
> > + return (strncmp(self, remote, strlen(self))) ? false : true;
> > +}
> > +
> > +ssize_t intel_gvt_get_vfio_device_version_len(struct drm_i915_private *dev_priv)
> > +{
> > + if (!IS_GEN(dev_priv, 8) && !IS_GEN(dev_priv, 9))
> > + return -ENODEV;
> > +
> > + return PAGE_SIZE;
> > +}
> > +
> > +ssize_t intel_gvt_get_vfio_device_version(struct drm_i915_private *dev_priv,
> > + char *buf, const char *mdev_type)
> > +{
> > + int cnt = 0, ret = 0;
> > + const char *str = NULL;
> > +
> > + /* currently only gen8 & gen9 are supported */
> > + if (!IS_GEN(dev_priv, 8) && !IS_GEN(dev_priv, 9))
> > + return -ENODEV;
> > +
> > + /* vendor id + device id + mdev type */
> > + /* vendor id */
> > + cnt = snprintf(buf, 5, "%04x", PCI_VENDOR_ID_INTEL);
> > + buf += cnt;
> > + ret += cnt;
> > +
> > + /* device id */
> > + cnt = snprintf(buf, 6, "-%04x", INTEL_DEVID(dev_priv));
> > + buf += cnt;
> > + ret += cnt;
> > +
> > + /* mdev type */
> > + str = mdev_type;
> > + cnt = snprintf(buf, strlen(str) + 3, "-%s\n", mdev_type);
> > + buf += cnt;
> > + ret += cnt;
>
> Why not just one big snprintf?
>
> Dave

oh, right:)
I'll use one big snprintf in next revision. thank you:)

>
> > + return ret;
> > +}
> > +
> > +ssize_t intel_gvt_check_vfio_device_version(struct drm_i915_private *dev_priv,
> > + const char *self, const char *remote)
> > +{
> > +
> > + /* currently only gen8 & gen9 are supported */
> > + if (!IS_GEN(dev_priv, 8) && !IS_GEN(dev_priv, 9))
> > + return -ENODEV;
> > +
> > + if (!is_compatible(self, remote))
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
> > index 43f4242062dd..19f16eec5a4c 100644
> > --- a/drivers/gpu/drm/i915/gvt/gvt.c
> > +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> > @@ -105,14 +105,65 @@ static ssize_t description_show(struct kobject *kobj, struct device *dev,
> > type->weight);
> > }
> >
> > +#ifdef GVT_MIGRATION_VERSION
> > +static ssize_t version_show(struct kobject *kobj, struct device *dev,
> > + char *buf)
> > +{
> > + struct drm_i915_private *i915 = kdev_to_i915(dev);
> > + const char *mdev_type = kobject_name(kobj);
> > +
> > + return intel_gvt_get_vfio_device_version(i915, buf, mdev_type);
> > +}
> > +
> > +static ssize_t version_store(struct kobject *kobj, struct device *dev,
> > + const char *buf, size_t count)
> > +{
> > + char *remote = NULL, *self = NULL;
> > + int len, ret = 0;
> > + struct drm_i915_private *i915 = kdev_to_i915(dev);
> > + const char *mdev_type = kobject_name(kobj);
> > +
> > + len = intel_gvt_get_vfio_device_version_len(i915);
> > + if (len < 0)
> > + return len;
> > +
> > + self = kmalloc(len, GFP_KERNEL);
> > + if (!self)
> > + return -ENOMEM;
> > +
> > + ret = intel_gvt_get_vfio_device_version(i915, self, mdev_type);
> > + if (ret < 0)
> > + goto out;
> > +
> > + remote = kstrndup(buf, count, GFP_KERNEL);
> > + if (!remote) {
> > + ret = -ENOMEM;
> > + goto out;
> > + }
> > +
> > + ret = intel_gvt_check_vfio_device_version(i915, self, remote);
> > +
> > +out:
> > + kfree(self);
> > + kfree(remote);
> > + return (ret < 0 ? ret : count);
> > +}
> > +#endif
> > +
> > static MDEV_TYPE_ATTR_RO(available_instances);
> > static MDEV_TYPE_ATTR_RO(device_api);
> > static MDEV_TYPE_ATTR_RO(description);
> > +#ifdef GVT_MIGRATION_VERSION
> > +static MDEV_TYPE_ATTR_RW(version);
> > +#endif
> >
> > static struct attribute *gvt_type_attrs[] = {
> > &mdev_type_attr_available_instances.attr,
> > &mdev_type_attr_device_api.attr,
> > &mdev_type_attr_description.attr,
> > +#ifdef GVT_MIGRATION_VERSION
> > + &mdev_type_attr_version.attr,
> > +#endif
> > NULL,
> > };
> >
> > diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> > index f5a328b5290a..4062f6b26acf 100644
> > --- a/drivers/gpu/drm/i915/gvt/gvt.h
> > +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> > @@ -687,6 +687,12 @@ void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu);
> > int intel_gvt_debugfs_init(struct intel_gvt *gvt);
> > void intel_gvt_debugfs_clean(struct intel_gvt *gvt);
> >
> > +ssize_t intel_gvt_get_vfio_device_version(struct drm_i915_private *i915,
> > + char *buf, const char *mdev_type);
> > +ssize_t intel_gvt_check_vfio_device_version(struct drm_i915_private *dev_priv,
> > + const char *self, const char *remote);
> > +ssize_t
> > +intel_gvt_get_vfio_device_version_len(struct drm_i915_private *dev_priv);
> >
> > #include "trace.h"
> > #include "mpt.h"
> > --
> > 2.17.1
> >
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
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